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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: KatManDEW on February 19, 2009, 01:17:36 AM

Title: To segment or not to segment?
Post by: KatManDEW on February 19, 2009, 01:17:36 AM
What's segmented memory? How do I know if I have it? And do I want it? (me thinks not?)
Title: Re: To segment or not to segment?
Post by: Matt_H on February 19, 2009, 01:21:47 AM
It's a feature of the Picasso II to allow it to squeeze into an already-full Zorro II memory space at the expense of a huge performance hit.

You want it only as a last resort. Probably better to lose some Fast RAM elsewhere in order to use a non-segmented Picasso.
Title: Re: To segment or not to segment?
Post by: save2600 on February 19, 2009, 01:32:19 AM
I'll second that emotion. Segmented memory is just that: memory allocated/utilised in small chunks. 64k in the case of the Picasso card. Regular non-segmented memory access is up to 2mb.

Best lose some fast ram before reverting to segmented.
Title: Re: To segment or not to segment?
Post by: KatManDEW on February 19, 2009, 01:36:09 AM
Thanks for the info. I had no idea what it applied to, but it turns out is is something the applies to my situation, because I have a Picasso II.

How do I check to see if my Picasso memory is segmented, and how would I change it?

Thanks again.
Title: Re: To segment or not to segment?
Post by: Tension on February 19, 2009, 02:14:08 AM
Put it in a sink full of water, and if it floats, it`s segmented.

Alternatively just run it under a warm tap for about 2 minutes.
Title: Re: To segment or not to segment?
Post by: save2600 on February 19, 2009, 02:46:20 AM
Memory is segmented on the Picasso via a single jumper on your video card.

The FOUR chips to the right of the blitter (closest to the VGA connector) is the jumper you need to be sure is OPEN. In other words - not connected. If that jumper is "jumped", then you are running your card in segmented mode. Not cool.

BTW: all of this segmented garbage is rubbish if you are using 32-bit ram (non Zorro II memory cards). There is no need to worry about segmentation if your RAM usage is above typical memory allocation of the Zorro II standard.
Title: Re: To segment or not to segment?
Post by: Matt_H on February 19, 2009, 02:47:16 AM
Quote

Tension wrote:
Put it in a sink full of water, and if it floats, it`s segmented.

Alternatively just run it under a warm tap for about 2 minutes.

Or, see if the segmentation jumper is set. One of the hardware databases can show you where it is on the board.
Title: Re: To segment or not to segment?
Post by: KatManDEW on February 19, 2009, 03:02:22 AM
I found it and it's not jumpered. Thanks.
Title: Re: To segment or not to segment?
Post by: Argus on February 21, 2009, 11:20:27 AM
Just for the record, the C=Lowell Graphics Card and Macrosystems' RetinaZ2 cards also used segmented memory.  In the case of the Lowell card, you can even use CybergraphX with it.   :-)

Interestingly, the get the Lowell card to work with Cybergraphx you need to just like other graphics cards have enough Zorro2 memory space for the card's 1.5Mb of segemented graphics memory.  There is some kind of trick involved to make the segmented memory work like other non-segmented graphics cards, has to do with how EGS worked iirc.  There of course should have been a way to make the RetinaZ2 also work this way and there was supposedly a beta driver but I've never seen it.
Title: Re: To segment or not to segment?
Post by: bloodline on February 21, 2009, 02:31:42 PM
Quote

Tension wrote:
Put it in a sink full of water, and if it floats, it`s segmented.


:lol: :lol: :roflmao: :lol: